82 gs550L bogs down

[Aaron]

Hi all,

I have a 1982 GS550L which has a severe lack of power below 3000rpm. Its been in storage for a couple years, but I just put a new battery and she started up. It pulls good above 3000rpm but any load on it below there it bogs down and dies.

Previously it ran really good after the carbs where cleaned and synced. However I changed the rear tire, but couldn't get the axle out with out removing the exhaust. I think this is the cause of the trouble, or am I missing something? Whats the trick to getting exhause back on and sealed tight? I did see a smallish hole 1/16" on the bottom of both pipes in the same spot. Could that be the problem?

Thanks
Aaron

[Steve]

That little hole is not the problem. That is likely a drain hole for condensation. If it is at the lowest point of the muffler, it's a drain.

And, I think you have really answered your own problem. Take a look at what you wrote, with some of the 'extra' stuff taken out:

Its been in storage for a couple years, ...
Previously it ran really good after the carbs where cleaned and synced.

What preparations did you make to put it in storage? If you just parked it, you problem is dirty, gummed-up carbs. The jets in the carbs, especially the low-speed jets, are small and easily plugged by the crud left behind by evaporating gasoline. To me, it sounds like it's time for another carb cleaning and sync. 8-[

By the way, welcome to the forum. BassCliff will be along shortly with the 'unofficial' welcome, so this will have to to until he gets here.





HEY, BASSCLIFF, ... ANOTHER NEWBIE!! \\/

.

[Aaron]

Thanks Steve, Sorry I wasn't more clear. It never ran the same after I put the exhaust back on. Last night I removed it to have a look see, and noticed a slight blueing on #3 right where the exhaust goes into the block. I tried to put them back on and had noticeable exhaust leaking out of #1 this time, and had the same bogging issue. Is it adviseable to use more than a single gasket per pipe?

Aaron

[waterman]

Aaron,
Welcome to forum. It is possible to add a second gasket but more than likely one will seal well enough. When you removed exhaust, did you separate center downpipes from outer pipes? If so have you tightened the center pipes back together without losing the sealing tape between pipes?

I would bet that you may not have the pipes fully seated into the heads. These can be a royal pain with the weight of mufflers hanging down. I have found a little persuasion is needed, I usually end up whacking the downpipes with a rubber mallet to get them to seat. Whatever you do, don't get carried away with trying to torque down the exhaust bolts to seat pipes. You will either break exhaust flanges or strip bolt holes in head. Remember to use antisieve lubricant on bolts.

If you have a new set of exhaust gaskets, remove old ones from head and install new. The old ones usually can be dug out. Good luck.

[Aaron]

The clamps on the center pipes were loose, so I did tighten them. The pipes were never separated, they're pretty rusted and that scared me. The gasket material doesn't look too good so I left them alone.

I'll have to order another set of gaskets for pipes to head conection. Is there a specific order of torquing the bolts to get them to seat properly? I couldn't tell if there was a orientation needed for the flange clamps either?

What is the theory behind a leaky exhaust and bad stalling/bogging problems?

[waterman]

There is a specific orientation of the flanges, they only go one direction.
I would concentrate on making sure that the pipes seat themselves into the head first. I had to coax mine around till I hit the sweet spot where they slid into place. Then it is simply a matter to rotate flange to correct position and tighten bolts. I would try this before gaskets, they will usually seal even if kinda grungy.

My theory on the exhaust leak affecting the motor performance is simply that it ran fine before removing exhaust, should run same afterward. In actuality, an exhaust leak will make motor run leaner--less restriction. On my KLX, I lost an exhaust gasket and on high rev deceleration would get a nice load pop out of it.

[Aaron]

I lost an exhaust gasket and on high rev deceleration would get a nice load pop

Yup, me too.

There is a specific orientation of the flanges, they only go one direction

That explains why even after retapping I feel resistance too early when tightening the bolts back on. I have a new set of gaskets on order, which should arrive soon. I'll have to play around and them mark them when I take them off this time.

I've been trying to seat the pipes by myself, do you think an extra set of hands would help? I think a rubber mallet is calling me. On certain pipes I could feel a little give, where the flange would pull them farther into the heads. #3 on the other hand I really couldn't get to budge, it didn't seem like it would go all the way in.

[waterman]

And extra set of hands can help if they are patient. I found that I had to lift the muffler end to mount height in order to get pipes to line up. From there a lot of cursing and beating with mallet is in order--you know standard operating procedure:-D! I found that pipes go straight into heads when correct angle is reached, then the whole unit will slide into place. I know this sounds simplistic but once you get it to fit once you will know what I mean.

Look at the exhaust flanges, you will see that bolt holes are off center. On my 650, the flange cooling fins are also asymmetrical, shorter to one side and longer on the other. When installed, these stayed consistent across engine. Not sure if this applies or makes sense.

[Aaron]

Things got worse. A whole lot worse. I talked to a friend and suggested to check for air leaks. So I figured what could it hurt to check, better off knowing she's good to go and the exhaust is the culprit. Nope I started it up sans pipes squirted a little carb cleaner at the intake pipes, and got a not so little ball of flames. I managed to get it out before too much harm, I think.

It looked like it was leaking at the heads. Out come the carbs, off come the intake pipes. I replaced these during the carb rebuild 4-5 years back (new O-rings). What I found is the O-rings were slightly swollen. Still pliable, but there was a little nibbling around some of the edges. Looking at the flanges on the pipes the O-ring groove is really off center, not like the one shown on http://cycleorings.com/intake.html It seems my Orings have to seat right at the edge of the boss on the heads. I just ordered new O-rings so we'll see what happens next.

Thats just the tip of it. If that goes well I have a messed up thread on the heads for the exhaust pipe. I cracked the first time around at the tire change. So I added a heli-coil and tried to JB weld it back in place. I put a stud in that one so I wouldn't have to mess with it in the future. (I have always used silver paste to prevent stuck bolts.) Well the stud backed out and the boss cracked off more. The Helicoil is still in there, but only just over half of the aluminum is around its circumference holding it in place. Any suggestions on how to deal with the cracked aluminum?

Aaron

[Aaron]

Well last night I dug into the carbs. Strangely #4 was missing the CV slide spring. I thought that the slide was gunked up because in wouldn't return, but that wasn't the case. What would be the effect of this spring missing?

Another thing I found was that #1 pilot was blocked on the bottom hole, #3 slightly less. Would this be the cause of my poor idle?

Aaron

[uudfourty]

That certainly may have something to do with it.:-D